| NWS Forecast for: St. Charles County Issued by: National Weather Service Saint Louis, MO Last Update: 243 PM CDT Mon May 18 2026 |  |
Tonight: Mostly cloudy with a chance of thunderstorms. Showers likely, mainly this evening. Some thunderstorms may produce heavy rainfall. Lows in the upper 60s. South winds 10 to 15 mph with gusts up to 25 mph. Chance of rain 70 percent. Tuesday: Mostly cloudy. A chance of showers and thunderstorms in the morning, then showers and thunderstorms likely in the afternoon. Some thunderstorms may produce heavy rainfall. Highs in the lower 80s. Temperature falling into the mid 70s in the afternoon. Southwest winds 10 to 15 mph with gusts up to 25 mph. Chance of rain 70 percent. Tuesday Night: Showers likely. Thunderstorms likely, mainly in the evening. Cooler with lows in the mid 50s. North winds 5 to 10 mph. Chance of rain 70 percent. Wednesday: Mostly sunny in the morning, then becoming mostly cloudy. A 20 percent chance of showers. Cooler with highs in the upper 60s. North winds 5 to 10 mph. Wednesday Night: Mostly cloudy. Lows in the lower 50s. Northeast winds 5 to 10 mph. Thursday: Partly sunny. Highs in the lower 70s. Thursday Night: Mostly cloudy. A slight chance of showers in the evening, then showers likely with a slight chance of thunderstorms after midnight. Lows in the upper 50s. Chance of rain 60 percent. Friday: Showers likely. A slight chance of thunderstorms in the morning, then a chance of thunderstorms in the afternoon. Highs in the mid 70s. Chance of rain 70 percent. Friday Night: Mostly cloudy with a slight chance of thunderstorms. A chance of showers, mainly in the evening. Lows around 60. Chance of rain 50 percent. Saturday: Mostly cloudy with a slight chance of showers in the morning, then partly sunny with a chance of showers with a slight chance of thunderstorms in the afternoon. Highs around 80. Chance of rain 40 percent. Saturday Night: A slight chance of thunderstorms in the evening. Mostly cloudy with a slight chance of showers. Lows in the lower 60s. Chance of rain 20 percent. Sunday: Partly sunny with a chance of showers with a slight chance of thunderstorms. Highs in the lower 80s. Chance of rain 40 percent. Sunday Night: Mostly cloudy with a 40 percent chance of showers. Lows in the mid 60s. Memorial Day: Partly sunny with a chance of showers. A slight chance of thunderstorms in the afternoon. Highs in the mid 80s. Chance of rain 40 percent. | |
| Zone Forecast: St. Charles County | |
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